Vibratory electromagnetic apparatus



1945- H. v. HARDING VIBRATORY ELECTROMAGNETIC APPARATUS 2 Sheets-Sheet 1 Filed July 19, 1945 INVENTORS HENRY \/.HARDING ATTORNEY Aug. 21, 1945. H. v. HARDING VIBRATORY ELECTROMAGNETIC APPARATUS Filed July 19, 1943 2 Sheets-Sheet 2 INVENTORS HENQY V. HARDING ATTORNEY Patented Aug. 21, 1945 2,883,382 VIBBATOBY ELECTROMAGNETIC APPARATUS Henry V. Harding, Royal ak, Mich, auignorto Elox Corporation, a corporation of Michigan Application July 19, 1943, Serial No. 495,382 2 Claims. (Cl. 219l) My invention pertains to improved vibratory electromagnetic devices, and more particularly to such devices for use in vibratory apparatus for working on metals.

It is an object of my invention to provide improved electromagnetic apparatus for use in vibratory devices, tools and the like, and which is compact, sensitive, self-contained and has ample overload capacity.

It is also an object of my invention to provide improved electromagnetic apparatus which will be internally cooled and, requiring no external ventilation, may be made very compact.

It is a further object of my invention to provide an improved electromagnetic device which is especially useful for operating vibratory tools on metals, and wherein the energization may be controlled through the metal.

The invention itself, however. both as to its construction or organization and its use or method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments, when read in conjunction with the accompanying drawings, in which similar reference characters are applied to corresponding elements throughout, and wherein:

Fig. l is a side elevational view partially broken away and sectioned to show structural details;

Fig. 2 is a plan view:

Fig. 3 is a cross-sectional view on line 3-! of Fi 1; f e

Fig. 4 is a diagrammatic view representing the winding of the new structure and the armature core member;

Fig. 5 is an enlarged sectional view showing the self-centering chuck holding and connecting coolant through a hollow electrode adjacent a piece of work;

Fig. 6 is a wiring diagram, schematically representing the connection of the apparatus with the work and a source of electrical energy; and

Fig. 7 is a view similar to Fig. l, but showing a difierent embodiment-of the field and armature structure which may be utilized in my vibrating apparatus.

Referring more specifically to Figs. 1, 2, and 3 of the drawings, I have shown my apparatus embodying an improved electromagnet, field and armature arrangement which is especially adapted device has a solenoid or winding ll wound of a conductor of a low resistance metal, such as copper, silver or the like, and of tubular cross-section through which any suitable coolant medium may be circulated for internally cooling the winding while electrical current is passing therethrough in the operation of the device. Although shown open. for clearness, the coils of the winding I I may be wound quite closely with a minimum space for insulation, such as baked enamel or other material, as hot spots can not develop and injure the insulation and space for ventilating ducts is not required because of being directly cooled.

The field structure provided to reduce the reluctance of flux paths in the magnetic circuit is of an improved construction which greatly reduces the heating and losses caused by eddy currents and hysteresis losses and which is compact and self-contained. The improved field structure comprises an enclosing shell having cylindrical side walls I! made of high quality term-magnetic material. This shell I! is preferably formed by winding 9. thin sheet of metal in overlappin spiral fashion, when viewed from the end, and as diagrammatically represented in Fig. 4. The side for cool and durable operation on heavy work over long periods of time, and which is especially adapted for vibrating metallic elements. electrodes, or tools. on metals, and which may also control the energizing of the device.

walls It are wound to enclose a space for receiving the solenoid winding and are wound until ample f erro-magnetic metal is provided in the flux paths of the magnetic circuit, the outer end and overlapping layers being then secured by an elongated fastening member or rivet H, as shown in Figs. 3 and 4. I

The cylindrical field structure shell i3 is closed at the ends by end walls It which are, as shown in Fig. l, of flat disc-like conformation formed by stacking thin circular pieces of high grade ferromagnetic sheet metal of a diameter substantially equal to the outer diameter of the cylindrical side walls. The thin laminations of the end walls of field structure it are secured snugly together, as by rivets 2 l. The lower end wall is provided with a central aperture 23 of a suitable size and shape to closely but freely pass one end of a reciprocatable core or armature 25 which is disposed axially in the solenoid winding ii with one end projecting out through said central aperture.

The reciprocative core or armature 25 is preferably fabricated by winding a strip of thin sheet ferro-magnetic metal in the manner indicated in Fig. 4, on the end of an elongated stem 29 to which it is secured as by transversely disposed rivets 3 i, shown in Figs. 1 and 3.

An outer enclosing and supporting structure is provided consisting of an outer casing 33 which My improved as is of a cylindrical conformation closed by end walls 34 and adapted to snugl receive and hold the cylindrical field structure with its end discs IS. The casing 33 is substantiall longer than the field structure, and a tubular spacer 35 is in sorted in the lower end under the field structure to hold these together in a firmly assembled rela tion with the upper field disc l9 snugly abutting the upper end wall of the outer casing. The casing is made of any suitable plastic composition which may be a phenolic condensation product or any other material sufllclently tough and durable, waterproof and electrically insulating, of which there are a large number. When assembling, the end walls 34 are secured by cement or screws into casing 33. The ends or terminal connections of the solenoid winding ll pass up through apertures having insulation bushings 31 in the upper field disc I 9 and out through the top wall 34 of the outer casing, the exposed ends of the conductor being suitably threaded to receive hose fixtures 39 for hoses 4|. One of the hoses 4| may connect to any convenient source of coolant (not shown) such as compressed air, a water tap or other source, and the other hose may discharge the cooling medium for suitable disposal. Electrical connections are made to the winding terminals in any convenient manner, as by solder, clamps or heavy clips (not shown) applied on the hose fixtures 39 for low resistance connection, as will be readily understood. A supporting pin 43 projects axially from the center of the top wall of the outer casing for convenient insertion into any conveniently adjustable chuck, on a drill press spindle or the like, whereby the device may be supported for convenient and ac curate positionin and adjustment up or down, and/or from side-to-side, in accordance with the nature of the work.

The armature extension or stem 29 projects downwardly and passes out through a hardened bushing 45 supported in the center of the bottom end wall of the outer casing. This bushing may be lubricated in any suitable manner, as through a tube 41 leading thereinto from an oil hole 49 in the side of the casing closed by a cover 50.

The outer projecting end of the extension 28 is threaded for screwing into a threaded aperture in the upper end of a block to which it may be secured as by a locknut 52. A threaded connector 53 extends into and from the bottom end of said block and supports a chuck or collet 55, wherein various metallic elements, electrodes or tools 51 may be conveniently inserted or replaced. Such an electrode or tool 51 may be connected through any suitable flexible conductor 59 connecting from the block 5i up to one of the fixtures 38 on top of the casing leading from one end of the winding ll so that the electrode may be controlled by energization of the solenoid.

A compression spring 60 is provided in concentric disposition on the extension 29 where, reacting between the lower end of the bushing 45 and a pair of adjustable locknuts 6|, it continuously urges the core armature and extension 29 to its lowest position. The lowest position of the core armature and extension assembly is predetermined by any suitable stop limit means, as by the upper end of the bushing 45 abutting the lower end of the core 25, as shown in Fig. 1.

In operation, one terminal of a suitable electrical source G, as shown in Fig. 6, such as a welding current source, is connected to the work piece 65, through a conductor 66, or the circuit may extend partly by a, ground circuit through the frame of a supporting structure, as will be readily understood. The other terminal of the electrical source G is connected through a conductor 81 to the other terminal 39, of winding H, which is not connected to the tool element. With the work piece 65 and the metallic element, tool or electrode 51 energized to opposite polarities from the current source, the engagement of the element upon the work causes current to flow through the solenoid winding II which quickly jerks up the electrode or tool element. This breaks the energizing circuit and deenergizes the solenoid. The element 51 is then quickly thrown down by the spring 59 and reengages the work. This cycle or operation is repeated in rapid succession causing the tool to vibrate on the work.

The tool 51 may be a riveting or peening hammer, a chisel or marking tool for cutting or marking sheet metal, as well as various other types of tools. I have foundthat by using a hollow or tubular electrode in the chuck and flowing a coolant over the work, it is possible to quickly and conveniently remove a piece of hard metal 68, such as a broken tap. Also a hole may in this manner be formed in hardened metal, as in a die for example. For this purpose a hose connection fixture 69 is provided in the side of the block 5i, and is connected to the discharge tube 4|, as shown in Fig. 5, for delivering compressed air, water, or other coolant, from any suitable source, so it flows down from the block through an axial passage H in the support and through the electrode 51 to the point, where the conduction of the electricity to the metal work piece causes hot spots and the coolant causes these to rapidly chip on, removing the broken tool or forming a new hole in hard metal.

Such electrode tubes 51 are preferably made of the softer metals, such as copper and other nonferrous metals. For convenience the electrodes, or other metal working tool elements, are preferably provided with an enlarged head 13 having self-centering conical surfaces. Theupper conical surfaces 15 of the head enter into the lower end of the aperture in the tubular connector 53 wherein it is clamped by screwing the chuck collar 55 up onto the lower end or the connector tube which, as shown in Fig. 5, centers the tool or element 51. When the element 5! is a tubular electrode, this self-centering arrangement serves to also establish alignment of the apertures H for passing a coolant down to the point of the electrode, to chip 011' metal as the electrode vibrates. In operation the coolant chills the hot spots formed on the hardened metal, and chips are rapidly broken off and are removed by the flow oi coolant medium into and out of the hole.

Fig. 7 shows another embodiment of the field and armature arrangement which may be advantageously utilized in my previously described apparatus for work of varying nature and conditions, In this embodiment, a stationary central core member 11 is provided extending axially through the shell 33 and the winding II with the upper end snugly abutting the upper field structure disc l9 whereto it is firmly secured, as by an elongated fastening member 79 passing up through an aperture therein and the upper end being secured, as by peening, to prevent its withdrawal. In this structure the lower field disc 01' the field structure has been removed and the lower end of the shell i3 is open exposing an eil'ective annular air gap 80 extending around between the lower end of the central core member 11 and the lower edges of the cylindrical field structure I3. Exposed to this annular air gap is an armature BI of a circular or disc shape. The armature 8| is made of good quality ferro-magnetic material, and may preferably be fabricated by stacking together a large number of thin laminations of the sheet metal and then rigidly securing together, as by a plurality of rivets 83 passing therethrough. The armature 8| i secured on the upper end of the extension or stem 29 which has a reduced end portion passing therethrough and peened over.. The extension 29 passes slidably down through the hardened bush-- ing secured in and passing through the lower end wall of the casing, as in the first embodiment, for supporting a connection block and chuck 55 for vibrating metal working elements 51. As in the flrst embodiment, the extension 29 and the armature are biased by gravity or a spring to a predetermined position from which it is moved when the structure is magnetized by current in a winding I I disposed around thecentral core II in the cylindrical shell I3. Although the winding I I could be independently controlled, it is preferably energized and controlled through the metal being worked on. by connecting one end of the winding I I through the conductor 59 to the sliding extension 29 and the tool or electrode which it vibrates, as in the first embodiment. Also the winding II is of tubular conductor for cooling, by flowing coolant therethrough, while carrying the heavy electrical currents which may be applied.

In operation, my second embodiment is utilized by inserting suitable electrodes, tools or other metal working elements in the chuck 55 in the manner, and for the purposes described, with ref erence to the first embodiment and which will therefore not be repeated. My second embodiment, shown in Fig. 7, has lighter weight in the vibrating parts and it is therefore more sensitive. Also the movements of the armature tend to fan and circulate the air, and the electromotive arrangement has difierent stroke characteristics useful for operating under various working conditions.

My vibratory electromagnetic metal working device is compact and self-contained, is cool operating and has ample over-load capacity.

I do not wish to be restricted to the specific structural details, arrangement of parts or circuit connections herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of my invention.

I claim:

1. In a vibratory electromagnetic device for working on metals the combination of, a solenoid winding, said winding being wound of tubular metal so that a cooling medium may be circulated therethrough, a core reciprocatably disposed in and extending from said winding, a field structure associated with said winding and core for reducing the reluctance of the magnetic flux paths, conductive means connecting one terminal of said winding to said core and extension, means for guiding reciprocating movements of said core, resilient means tending to urge said core to a predetermined position from which it is attracted when the winding is energized, means limiting the predetermined position to which the core is moved by said resilient means, and a chuck on the extending end of said core, said chuck being constructed to removably mount an elongated, hollow, metallic element therein for engaging metal to be worked upon movement of said core, said chuck having a fluid flow passage therein communicable with said hollow element.

2. Metal working apparatus comprising an electromagnetic winding, said winding including a tubular metallic conductor so that coolant fluid and electric current may flow throughthe winding simultaneously, an armature structure disposed movably adjacent said winding for movement thereby and having an extension adapted to support a hollow electrode, a fluid flow passage in said extension, and electric and fluid flow conducting means connected to one end of the conductor and connected to said armature structure for movement therewith and communicating with the passage in said extension for conducting coolant fluid therethrough and electrically connecting said conductor and extension, said last named means including a flexible tube for conducting the coolant fluid and an electrical conductor within said tube providing the electrical connection.

HENRY V. HARDING. 

